7 Boron Trifluoride Uses: Facts You Should Know!

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Boron trifluoride is an inorganic compound having the molecular formula BF3. BF3 is a colorless, pungent-smelling noxious gas. Let us discuss the uses of BF3 in brief.

  • A Reagent or a Catalyst in Organic Synthesis
  • Extinguishing Agent for Magnesium Fires
  • Soldering Fluxes for Magnesium
  • Fiber Optics
  • Fumigation
  • Neutron Measurement
  • Petroleum Cracking and Desulphurization

A Reagent or a Catalyst in Organic Synthesis

BF3 is act as Lewis acid because of the vacant p-orbital on Boron atoms which accepts a pair of electrons. Because of Lewis acidic nature of BF3 is act as a reagent or catalyst in various organic reactions as follows,

  • BF3 initiates polymerization in different unsaturated hydrocarbons like alkene, ethers, etc. Some examples of such polymerizations are, polymerization of oxetanes with azidomethyl substituents and the polymerization of isobutylene to polyisobutylene.
  • BF3 can incorporate as a Lewis acid catalyst in Friedel Craft reaction (alkylation and acylation) of Benzene that generates substituted benzene. The advantages of using BF3 as Lewis acids over other are that, it gives less by-product, more yield of product and forms a stable coordination compounds.
  • In forming Esters from the reaction between carboxylic acid with an alkene, BF3 acts as a catalyst.

RCOOH + CH2=CH2 + BF3  =   RCOOC2H5

  • Alkyl alcohol, when it reacts with carbon monoxide in the presence of BF3, gives carboxylic acid.

ROH + CO + BF3  =  RCOOH

  • BF3 also mediates the Nitration and Sulphonation of Benzene as catalyst.
  • BF3 catalyzes the amide formation reaction which takes place by hydrolysis of alkyl nitrile. The advantage of BF3 as a catalyst is that it prevents further hydrolysis of amide to acid. The reaction of amide formation as follows,

R-CN + H2O + BF3  =  R-CONH2

  • BF3 is used as a building block for the synthesis of boron compounds like Diborane (B2H6) which is a very important boron compound and also other boron halides.
  • BF3 is used to form stable adducts with Lewis bases, such as fluorides and ethers, like NH3, H2O, Et2O, CsF etc.
  • BF3 on hydrolysis gives boric acid and fluoroboric acid.
  • BF3 is used as a catalytic reagent in the multi-step-synthesis of many natural products. Natural products like (±) junenol, (±) acalomone, pisiferic acid, 6-methoxy-2-tetralone, cuprane, (±) karahana ether etc.
  • BF3 also found application in condensation, cyclization, isomerization, molecular rearrangement etc.

Extinguishing Agent for Magnesium Fires

BF3 can be incorporated as a magnesium fire extinguisher as molten magnesium fire can not be extinguished by water, carbon dioxide, halogens, nitrogen etc. For that, we must incorporate Class D extinguishers or smother with dry sand, dry clay, dry ground limestone, dry graphite, Boron trifluoride (in some cases) etc.

Soldering Fluxes for Magnesium

  • BF3 found its application as magnesium soldering flux. Magnesium metal and its alloys are difficult to solder because magnesium burns fair easily; it is required to heat up to the temperature where it goes in molten form.
  • BF3 is used as an extinguishing agent for magnesium fires, so for that reason, BF3 works very well as a soldering flux for magnesium and its alloys.   

Fiber Optics

BF3 is used to make high-strength boron filaments, lightweight materials. Because of this, boron filaments are widely used in optical fiber manufacturing.

Fumigation

BF3 is a colorless, noxious gas with a pungent odor. Because of the noxious nature of this gas, it is used as a fumigant.

Neutron Measurement

Boron trifluoride gas is used for slow neutron detection, whereas a BF3 tube is used as a detector. Boron nucleus can absorb neutrons and emits Alpha particles (α-particles) which can be counted. Ionization chambers with boron-coated electrodes or the proportional.

Petroleum Cracking and Desulphurization

BF3 found application in petroleum cracking and desulphurization of crude oil.

Conclusion

BF3 is a Lewis acid found to be very useful in various chemical reactions Friedel Craft reaction, polymerization, etc. It is also used to make boron fibers in fiber optics because of its high strength and light-weightiness. BF3 acts as a magnesium fire extinguisher, fumigant and so on.